At ETH Zurich, a team of students has developed a high-speed, multi-material metal 3D printer: a laser powder bed fusion system that rotates both the powder deposition and gas flow nozzles during printing. This allows the machine to process multiple metals simultaneously, without downtime, potentially transforming metal additive manufacturing by cutting production time and costs.
The system was created by six Bachelor’s students in their fifth and sixth semesters as part of the Focus Project RAPTURE in the Advanced Manufacturing Lab, under the supervision of ETH Professor Markus Bambach and Senior Scientist Michael Tucker. In just nine months, the team designed, built, and tested the printer. While intended mainly for aerospace applications with cylindrical parts like rocket nozzles and turbomachinery, the technology also has broad potential across mechanical engineering.
Rotational Printing and Multi-Metal Capabilities
Tucker explained the effort stemmed from a very specific challenge: creating bi-liquid-fueled rocket nozzles for ARIS, the Swiss Academic Space Initiative, which is building its own rockets with the goal of eventually reaching space. Within the next few years, ARIS hopes to reach the Kármán Line—the internationally recognized boundary of space at 100 kilometers altitude, beyond which traditional aircraft cannot fly.
Rocket nozzles must withstand extreme heat and pressure over long durations, ideally by combining different metals. “For small players like our student rocket team, this sort of multi-material technology has up to now been too complex and too expensive, putting it out of reach,” said Tucker.
At the core of the RAPTURE machine is a rotating platform that enables continuous, high-speed printing. Unlike conventional laser powder bed fusion systems, which pause between layers to apply new powder, the rotating design applies and fuses powder simultaneously. This boosts productivity and cuts manufacturing time for cylindrical components by more than two-thirds.
“This process is ideally suited to rocket nozzles, rotating engines and many other components in the aerospace industry,” said Tucker. “They typically have a large diameter but very thin walls,” he adds. While the machine can also produce non-axisymmetric shapes or arrays of parts, the rotating method is especially effective for cylindrical geometries.
Another key advantage is the ability to process two different metals in one operation. Conventional systems require multiple steps and much larger quantities of powder—much of which becomes waste since separating mixed powders is still difficult. The RAPTURE system only deposits material where it is needed, minimizing waste. To further enhance quality, the machine integrates a gas flow system that blows inert gas over the fusion zone to prevent oxidation while by-products are extracted through an outlet.
Custom-Built Components and Future Potential
Building the machine involved solving major engineering challenges, such as synchronizing the scanning laser with the rotating gas inlet and powder supply. Since many of the required parts did not exist commercially, the students designed custom components, including a rotatable gas connection and an automatic powder refill system. Despite these hurdles, the team succeeded in creating a system that already looks close to industrial application. “The fact that a team of students developed and built a functioning machine in nine months is pretty remarkable,” said Tucker.
Beyond ARIS and aerospace, the team sees applications in aircraft turbines, gas turbines, and electric motors, where ring-shaped geometries are common. Recognizing its novelty and commercial potential, ETH has filed a patent for the rotary multi-material laser powder bed fusion technology, which has been nominated for the ETH Spark Award.
So far, the prototype has produced parts up to 20 cm in diameter, and the researchers are now working on scaling the process to larger sizes and higher speeds. They are also seeking industry partners to help bring this technology into broader use.
Advances in LPBF
The RAPTURE project is part of a growing wave of innovation in laser powder bed fusion. In April, ADDiTEC, a US-based developer of advanced metal additive manufacturing technologies, unveiled its first Laser Powder Bed Fusion system during RAPID + TCT 2025 in Detroit. The new platform, called Fusion S, expands the company’s technology offerings, which previously focused on Directed Energy Deposition (DED) and Liquid Metal Jetting (LMJ). With this release, ADDiTEC becomes one of the few companies globally offering three complementary metal additive manufacturing technologies.
Similarly, Irish medical device manufacturer Croom Medical introduced TALOS, an LPBF platform for 3D printing tantalum (Ta). The company describes TALOS as a breakthrough for medical implants and industrial applications, highlighting the expanding capabilities and versatility of LPBF technology across sectors.
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Featured photo shows The new 3D printer allows two different materials to be simultaneously fused by a laser on the rotating platform. Photo via ETH Zurich.
